1. Technical Field of the Invention
The present invention relates to an ink-jet type recording apparatus which has a recording head movable in the widthwise direction of recording paper and forms an image on the recording paper by ejecting ink droplets thereto in correspondence with print data, and more particularly to a technique for managing ink in an ink cartridge.
2. Prior Art
An ink-jet type printer is an apparatus which has an ink-jet type recording head which receives a supply of ink from an ink storage means as well as a paper feeding means for relatively moving recording paper with respect to the recording head, and ejects ink droplets to the recording paper while moving the recording head in correspondence with a print signal, thereby effecting recording. In the light of the fact that the ink, i.e., a liquid, is handled, operations are performed, including the filling of ink into the recording head, forcibly sucking and discharging the ink from the recording head to prevent clogging due to the vaporization of an ink solvent, and ejecting ink droplets from nozzle openings in the recording head by supplying drive signals unrelated to print data.
The processing operation for the forcible discharge of the ink, which is effected for overcoming the clogging of the recording head, is commonly referred to as a cleaning operation. This processing is one in which, in a case where printing is resumed after a long period of downtime, or in a case where a user has pressed a cleaning switch to overcome the clogging, the ink droplets are discharged from the nozzle openings by sealing the recording head with a capping means and by allowing negative pressure to act. The cleaning operation is subsequently accompanied by a wiping operation using a wiping blade member formed from an elastic plate such as rubber.
The operation in which the ink droplets are ejected by applying the drive signal to the recording head is commonly referred to as a flushing operation, and is an operation in which broken menisci in the vicinities of nozzle openings are recovered by wiping or the like during the cleaning operation. The flushing operation can also be performed for each fixed period for the purpose of preventing the clogging at the nozzle openings where the amount of ejection of ink droplets is small during printing.
In the light of the fact that ink which dries speedily on the recording paper is used due to high-density arrangement of the nozzle openings and for the improvement of print quality, the following problems are encountered. One problem is that because the sizes of the nozzle openings of the recording head are small, and the ink attached to a plate dries in a very short time, the viscosity of the ink in channels in the nozzle openings, a pressure generating chamber, a reservoir, and the like, which constitute the recording head, increases in a short time, resulting in faulty ejection of ink droplets. Another problem is that the viscosity of the ink attached to the nozzle surface increases due to the discharge of the ink in the cleaning operation, enters the nozzle openings in the subsequent wiping operation, and causes air bubbles to grow due to a pressure change caused by a subsequent flushing operation, with the result that, faulty ejection of ink droplets can result immediately after the cleaning operation.